Visa for Turkey

We are British citizens, resident in the UK. We will be going on a cruise to Eastern Mediterranean in November. We will be visiting Turkey - 2 days - staying on board the cruise liner, but hopefully going ashore for either a planned excursion or independent stroll around Istanbul. Do we require a visa for such a short visit? If so, where can we obtain a visa for this sort of trip and what is the cost? Thanks in advance.

Try to have new or at least clean bank notes as torn or defaced notes are not accepted neither are Scottish notes for some reason. Here though even torn or defaced Turkish notes generally aren't accepted by traders either!!!